CHAPTER 18 THE PUBLIC TELEPHONE NETWORK # DEFINITIONS TERMS 1) It uses the largest computer network in the world to interconnect millions of subscribers in such a way that the myriad of companies function as a single entity. Public Telephone Network (PTN) 2) Identifies and connects the subscribers to a suitable transmission path. Switching 3) Supply and interpret control and supervisory signals needed to perform the operation. Signaling 4) The public telephone companies. Service Providers 5) 6) 7) 8) Equipment and facilities that are available to all public subscribers to the network. Another name for Public Switched Telephone Network (PSTN). The transmittal of digital information between two pieces of digital equipment. Any device used to originate and terminate calls and to transmit and receive signals into and out of the telephone network. Common Usage Equipment Dial-Up Network Data Transmission Instrument 9) The instrument is often referred. Station Equipment 10) The location of the equipment. Station 11) The operator or user of the instrument. Subscriber 12) The dedicated cable facility used to connect an instrument at a subscriber's station to the closest telephone office. Local Loop 11) Similar to local loop except trunk circuits are used to interconnect two telephone offices. Trunk Circuits Prepared By : JENNIFER F. DOCOT 112
12) The dedicated cable facility used to connect an instrument at a subscriber's station to the closest telephone office. Local Loop 13) Similar to local loop except trunk circuits are used to interconnect two telephone offices.. Trunk Circuits 14) A central location where subscribers are interconnected, either temporarily or on permanent basis. Exchange 15) Programmable matrices that provide temporary signal paths between two subscribers. Switching Machines 16) Exchanges connected directly to local loops. Local Exchanges 17 The first commercial telephone switchboard began operation New Haven, Connecticut. January 28, 1878 18) The first local telephone exchanges. Switchboards 19) A system of sensors, switches, and other electrical and electronic devices that allows subscribers to give instructions directly to the switch without having to go through an operator. Automated Switching System 20) Allowed subscribers to manually dial the telephone number of the party they wished to call. Mechanical Dialer 21) Commonly called for stepper or step-by-step (SXS). Strowger Switch 22) Simply the path over which voice, data, or video signals propagate. Circuit Prepared By : JENNIFER F. DOCOT 113
23) A programmable matrix that allows circuits to be connected tom one another. Circuit Switch 24) Telephone call completed within a single local exchange. Intraoffice Call 25) Telephone calls placed between two stations that are connected to different local exchanges. Interoffice calls 26) Another name for interoffice calls. Interswitch Calls 27) Telephone switching machines in local exchanges are connected to other local exchange office. Trunks or Interoffice Trunk 28) It is used to interconnect local offices that do not have interoffice trunks directly between them. An exchange without any local loops connected to it. Tandem Office 29) Switches that interconnect local offices only. Tandem 30) Trunk circuits that terminates in tandem switches. Tandem Trunk or Intermediate Trunk 31) 32) Interstate long distance telephone calls require a special telephone office. Provides telephone numbering system for the United States, Mexico and Canada. Toll Office North American Telephone Numbering Plan (NANP) 33) It allows many subscriber to share a limited number of lines to a central office switch. Concentrator 34) A path between two subscribers and is comprised of one or more switches, two local loops; and possibly one or more trunk circuits. Route Prepared By : JENNIFER F. DOCOT 114
35) A call that call cannot be completed because the necessary trunk circuits or switching paths are not available, the calling party receives an equipment busy signal. Blocking 36) A local exchange where subscriber loops terminated and received dial tone. Class 5 End Switching Office 37) Class 4 office having only outward and inward calling service. Class 4P Switching Office 38) Class 4 office provided human operators for both outward and inward calling service. Class 4C 39) Switching office that provide service to small groups of class 4 offices within a small area of a state. Class 3 Primary Center 40) Sectional centers that could provide service to geographical regions varying in size from part of a state to all of several states. Class 2 Sectional 41) Regional centers were the highest ranking office in the DDD network in terms of the size of the geographical are served and the trunking options available. Class 1 Regional Center 42) Toll trunks in tandem, excluding the two terminating links at the ends of the connection. Intermediate Links 43) 44) A global standard for telecommunications defined by the ITU. Refers to the exchange of information between call components required to provide and maintain service. Common Channel Signaling System No. 7 (SS7 or C7) Signaling Prepared By : JENNIFER F. DOCOT 115
45) An architecture for performing out of band signaling in support of common telephone system functions. SS7 47) Long distance access is now accomplished through an access point. Point of Presence (POP) 48) A telecommunications term that describes the legal boundaries for the responsibility of maintaining equipment and transmission lines. POP 49) Provide access to the SS7 network, access to databases used by switches inside and outside the network. Signaling Points 50) Codes that are carried in signaling messages exchanged between signaling points to identify the source and destination of each messages. Point Codes 51) Local telephone switches equipped with SS7 compatible software and terminating signal links. Service Switching Points 52) The packet switches of the SS7 network. Signal Transfer Points 53) It serves as an interface to telephone company databases. Service Control Points 54) Another name for service control points. Signal Control Points 55) Provides access from one level of the protocol to another Primitive Prepared By : JENNIFER F. DOCOT 116